The present invention relates to a control groove disposed on the cutting surface of a cutting tool or cutting element intended for working material in a manner which forms chips, or cuttings, the groove being provided with depressions which are juxtaposed in the transverse direction of the groove, which are parallel to one another, and which extend substantially over the length of the cutting edge.
It is known to provide a control groove in a cutting element for a metal working tool so that the element is able to deflect and break cuttings, or chips, the cross sections of which vary for different advancing speeds. Such a structure is disclosed in U.S. Pat. No. 3,187,406. For this purpose, the groove has a relatively small radius of curvature in the region adjacent to the cutting edge and a larger radius of curvature at a greater distance from the cutting edge.
When the tool is subjected to a slow advancing speed, the cutting, or chip, is already deflected at the beginning of the region having the larger radius of curvature. With a medium advancing speed, the cutting will place itself against the rearward portion of the region of larger radius of curvature, i.e., the portion which is further removed from the cutting edge. It is then deflected there. With a fast advancing speed, the cutting will completely brush past the control groove and is deflected and broken in the region of the transition between the groove and the cutting element surface disposed therebehind. However, when working with very narrow and thin cuttings, of the type generated in precision machining work, this solution has not been found to be fully satisfactory.
For a control groove of the above-mentioned type it has already been proposed, inter alia, to provide two depressions which are parallel to one another in the longitudinal direction of the cutting edge and which are separated from one another by a ridge. This structure serves the purpose of advantageously deflecting and breaking chips with an average cross section. Such structures are disclosed, for example, in German Pat. No. 1,602,968.